Percussion fuse



May 10, 1938. M, B RKI T 2,116,820

PERCUSSION FUSE Filed Oct. 16, 1956 INVENTOR NARCBIRKIGT ATTORNEYS Patented May 10, 1938 UNITED STATES 2116,820 PERGUS SION FUSE Marc Birkigt, Bois-Colombes, France Application October 16, 1936, Serial No. 106,033 In Belgium September 11, 1936 s (01. mass) 7 The present invention relates to percussion fuses for projectiles adapted to turn about their axis along their trajectory, and it is more especially, although not exclusively, concerned with fuses'ofthisv kind for projectiles of small calibre. I The object of the present invention is to provide a fuse of this kind which is better adapted to meet the requirements of practice than other fuses of the same kind made up to the present time.

According to an essential feature of the pres: ent invention, the striker of the fuse is provided with a locking pin or the like which locks the striker for a certain length of time and which is ejected from its housing by the centrifugal acceleration resulting from the rotation of the pro,- jectileabout its'axis, and said locking element is kept in active position, when the projectile is in the state of rest, by elastic means the action of which upon said locking element takes place in the same direction as that of the forces of inertia developed when there are positiveaccelerations of the projectile along its trajectory.

Another feature of the present invention consists in interconnecting the striker and the, cover plate. of the fuse in such manner that said striker,

U nce it is released, is unable to come accidentally into contact with the priming element of the fuse under the effect of the vibrations of the projectile along its trajectory, which might produce a, premature explosion of the projectile. Qther features of the present invention will res ult from the following detailed descriptionof a ,sp'ecific embodiment thereof.

A.preferred-embodiment of the present invention willbe hereinafter described, with reference to the accompanying drawing, given merely by way of example, and in which: l The only figure is an axial section of a percussion fuse made according to the present invention.

The'following description relates to the case of a percussion fuse more especially intendedfor a shell of small calibre adapted to be fired in a fire arm provided with riflings.

The fuse is devised in such manner that the :striker with which it is to be provided is locked for the desired period'of time by a locking pin or the like capable of being ejected from its housing, under the effect of the centrifugal acceleration resulting from the rotation of the projectile about its axis.

For this purpose, according, for instance to known arrangements, the body of the fuse consists of a metallic piece I which is provided at the rear end with a chamber 2 in which are housed a priming element 3 and-a detonator 4, this chamher being closed toward the front by thebody of the fuse itself, in whichare provided cylindrical bores 5,- preferably of increasing diameter toward 5 thenose of the fuse, so as to accommodate and guide a striker 6.

-.The nose of the fuse is fitted with a cover plate 1. l

" -I provide in the body of the fuse, in a direction at rightangles to that of the axis of said striker 6,. a housing 8 capable of guiding the displacements of a safetypin 9 the center of gravity of which is in eccentric position with respect to the axis-;;of--the fuse, saidjpin further including, for 5 instance, twobranches between which said striker can move in the direction of its axis, said striker being provided withia collar II), in such manner that its point; is kept at a. suitable distance from the priming element, of, the detonator.

According, to zthelessential feature of the present invention, this docking pin 9 is caused to coact: with an element capable of keeping it in position qand ,subjectedqto the-action of an elastic systems This elastic system keeps said element in active: position when the shell is in the position of rest, andit is arranged to act on said element in .the'same direction as the forces of inertia when there are positive accelerations of the shell along its trajectory.

. Although there are many possible embodiments of such a device, I have found that it is particularly advantageous to make use of that illustrated by the; drawing. I

- 'I'he element for keeping the locking pin 9 in position consists of a sliding part II, for instance of cylindrical shape, capable of moving in a bore [2 extendingin a direction parallel to the axis of the fuse, in the front part of body I, and opening into, housing 8, In other words, bore I2 is located 40 in the frontv part. of the fuse, with respect to housing 8. Member H is preferably, although not necessarily, fitted with an inclined portion, for instance of conical shape, l3, capable of coacting with a notch M, of corresponding shape,

provided for this purpose in pin 9.

The elastic system above referred to consists of a spring l5, for instance of the coil type, interposed between element II and the bottom of bore l2. Therefore this spring urges the locking element ll toward the rear of the projectile, by applying it into notch l4.

If desirable, I may also, eventually, provide means for braking the displacements of said element I I in its housing and therefore for delaying the release of pin 9, said means being preferably adjustable. For instance I might cause element I l to coact with a dash-pot of adjustable restricted section.

With the arrangement above described, I obtain a percussion fuse the operation of which takes place in the following manner:

1 As-long as the shell keeps, along its trajectory, a sufiicient positive, acceleration, spring JS and the. forces; of inertia-acting upon element I lovercome the thrust exerted by notch l4 upon the'en'd l3 of said element I I. When, as a consequence of the resistanceof air to the movement of the shell;

the acceleration of the shell drops to a lower value Of course, the position of the point of the ,tra., jectory of the projectile where this relea'sing'ac tion takes place-will-depend, among other things, upon the strength of spring l5fandthe-valueof the angle of conei3. .any case, this point is at a certain distance fromnthe muzzleof the gun from which .the projectilewasfired; which, for practical purposes, corresponds to a :safety of several meters.

Accordinglto another feature of the presentinvention, which is not necessarily combined with the arrangement :just above 'describe'd, the cover plate I of the fuse (which cover plate is then preferably given aconcave shape) and striker'li are interconnected, for instance by. securing one to the other. With this a'rr-angemenfiihere is no risk, once the striker is dis'er'igaged, of the point thereof coming accidentally into contact with the priming element 3 and causing' a premature explosion of the shell, since said'point-can come into contactwiththe priming element only after cover plate I has been brokenasa consequence of the crashing of the shell 'aga'inst anobstacle.

In a general manner,'while l haveg-inthe above descriptiomdisclosed what I deem to be practical and efficient embodiments 0f the present invention, itshould be Well understood that I -do-not wish to be limited thereto- =as' -there might be changes made in -'the' arrangement'ydisposition and form of the parts without -departing drom the principle of the present invention {as "compre hended within the scope th appendedclaims.

What I claim isz" 1. A percussion fuse which=domprises, '-in com bination; a' body' having a'longitudinal"akis; a detonator and a striker within saidbo'dyT-said detonator and said striker beingmovable relative to each other longitudinally of sa'idbody 'for bringing said striker in contact withsaid det onator, said body being-providedwith a trans% verse housing, a member s'lidable infsaidhousing for normally preventing said relative movement', said member havingits centerofgravity located in eccentric position with respect to the axis of said body and having an inclined surface at the front side thereof, an element movable in said body in a longitudinal direction thereof adapted to engage said member along said inclined surface so that an outward displacement of said member tends to thrust said element out of the Way, and elastic means for urging said element against .said member, saidelastic means acting on said element in the samedirectionas the forces of inertia developed by 'a positive acceleration of the fuse. 2. A percussion fuse which comprises, in coma-binati'on; a body having a longitudinal axis, a .detonator and a striker within said body, said detonator' and said striker being movable relative :to each other-longitudinally of said body for --br'inging said striker in contact with said detonator, said body being provided with a transverse housing, a member slidable in said housing for normally preventing said relative movement, said member having its center of gravity located in eccentricpositionwithrespectto the-axis-of said body, a bore in said body extending transversely to said. housing, said-member being provided with aconical hole at the front surface thereof, a member of cylindrical: -shape having" a conical end adaptedmo slide :in said bore and to'have its conical-end engaged in said hole; said bore extending from said housing toward the front end of said fuse, and a coil spring fitted in said bore so as to urge said cylindrical membe'routwardly from said boreand toward the 'rear of said body for keeping said'conical end-engaged in said conical hole as long as the acceleration is above a predetermined Value 5.1 l

3. -A fuse for a projeetileintended'to move along its trajectory with a rotary movement'aroundits axis, comprising in combination a fuse body, a detonator and a striker withi-n 'said body, said striker and said detonator being movable relative to'each'other for bringing said striker in contact with said detonaton-means for normally preventing *s'aid movement, said means i i comprising a transverse housing said body,a lockin g'member slida'blein said housing and'havin'g' its center of gravity located in eccentric positionwith respect to the axis of said body, "an'elemeritymovame in 1 said body independent of sai'd" striker anddetonator in a iongitaeinar directioir'of said body and adapted to engage said'member at lie-front side thereof and elastic means for urging said elenient against "said niemberin a'dirctiontoward the rear end of said fuseg'said'elasticnieansfbeing so tensioned that said mei'riber'is*retairied'in1locking position as longas theac'celeratioiiof'said p'ro jecti'le increases and saidmember'rismoved into unlocking position substantially- 'soon asj'the speed of saidprojectiledecreases. 

